The term “iliopsoas muscle” is used to describe one functional unit composed of two muscles; the iliacus muscle and the psoas major muscle, both acting together as the major flexor muscles of the hip.
In this tutorial, we will look at the origin, insertion, innervation, and action of both of these muscles.
Origin (proximal attachment):
Iliac fossa of the hip bone (Os Coxae).
Insertion (distal attachment):
Lesser trochanter of femur.
Femoral nerve (L2-L3).
Origin (proximal) attachments:
Vertebral bodies and transverse processes of T12-L4, Intervertebral discs between T12-L4, Costal processes of L1-L5 vertebrae.
Insertion (distal) attachments:
It forms a strong tendon with the Iliacus muscle, inserting into the lesser trochanter of femur.
Anterior (ventral) rami of lumbar plexus (L1-L3).
Action of Iliopsoas
- Flexes thigh at the hip joint.
- Laterally rotates thigh at the hip joint.
Furthermore, the iliopsoas muscle is an important postural muscle, helping in standing, walking, and running.